A water isotope (2H, 17O, and 18O) spectrometer based on optical feedback cavity-enhanced absorption for in situ airborne applications

Abstract

A water isotope (H-2, O-17, and O-18) spectrometer based on optical feedback cavityenhanced absorption for in situ airborne applications Kerstel, E. R. T.; Iannone, R. Q.; Chenevier, M.; Kassi, S.; Jost, H. -J.; Romanini, D. Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. O at high spatial resolution are required for this purpose. We present the design and laboratory performance of a device that will be used on high-altitude research aircraft. It is based on optical feedback cavity-enhanced spectroscopy (OF-CEAS), with better sensitivity than traditional multi-pass arrangements. It utilizes a near-infrared laser source, avoiding the need for cryogens. We demonstrate an airborne precision during tropospheric flight conditions of 1 ‰, 3 ‰, and 9 ‰ for δ 18 O, δ 17 O, and δ 2 H, respectively, for 30-s averaged data and a water concentration of about 200 ppm. With recent improvements we expect to remain within a factor of about three of these values under true stratospheric conditions (water mixing ratio ∼ 10 ppmv).PACS 07.88.+y; 42.55.Px; 42.62.Fi; 92.60.Hd; 92.60.Jq

Measuring variations of δ<sup>18</sup>O and δ<sup>2</sup>H in atmospheric water vapour using two commercial laser-based spectrometers: an instrument characterisation study

“…Several research instruments (Webster and Heymsfield, 2003;Kerstel et al, 2006;Sayres et al, 2009;Dyroff, 2010) and commercial measurement systems (Picarro, www. picarro.com; Los Gatos Research, www.lgrinc.com) based on cavity ring-down, cavity enhanced and tunable diode laser absorption spectroscopy have been proposed in the last decade.…”

“…Spectral selectivity and the sensitivity of the optical components as well as electronic noise associated with the setup limit the precision of infrared isotope ratio measurements (Paldus and Kachanov, 2005). Many recent studies indicate similar performance of laser and conventional IRMS systems in terms of precision (Kerstel et al, 2006;Gupta et al, 2009;Sturm and Knohl, 2010). Equally relevant for atmospheric field applications, however, is the overall measurement uncertainty resulting from a range of factors like calibration, sensitivity to variations in water concentration, and retention effects from the tubing (Brand et al, 2009;Schmidt et al, 2010;Johnson et al, 2011;Rambo et al, 2011).…”

Comparison of optical-feedback cavity-enhanced absorption spectroscopy and gas chromatography for ground-based and airborne measurements of atmospheric CO concentration

“…The laser spectroscopy technique going under the name of OF-CEAS was introduced by Morville et al (2005) and has been further detailed in different publications (Kerstel et al, 2006;Kassi et al, 2006;Ventrillard-Courtillot et al, 2009;Faïn et al, 2014;Maignan et al, 2014;Morville et al, 2014).…”

“…A normalization procedure of the absorbance scale is realized continuously based on cavity optical loss measurements performed by CRDS (Kerstel et al, 2006;Morville et al, 2014). Pressure and temperature stabilization of the sample inside the cavity allows for a real-time numerical fit of the measured absorption spectra with a reduced number of parameters (GorrotxategiCarbajo et al, 2013).…”

“…This has already been exploited in airborne atmospheric measurements of methane in Romanini et al (2006), water isotopes in Iannone et al (2009a) and Kerstel et al (2006), and in other fields using laboratory prototypes and commercial instruments (ProCEAS) as mentioned in the introduction section.…”